Apparatus for the control of highway crossing signals



Patented July 6, 1937 UNITED STATES APPARATUS FOR THE. CONTROL OF HIGH- WAY CROSSING SIGNALS James J. Vanhorn, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa, a corporation of Pennsylvania Griginal application January 11, 1936, Serial No.- 58,716. Divided and this application October I 27, 1936, Serial No. 107,847

9 Claims.

My invention relates to apparatus controlled by a train approaching a highway crossing for governing the operation of the highway crossing signal.

The present application is a divisional application of my copending application Serial No. 58,716, filed January 11, 1936, for Apparatus for the control of highway crossing signals.

A feature of my invention is the provision of lo novel and improved apparatus controlled by a train approaching a highway crossing for preventing a continued operation of the highway crossing signal in the event the train should stop within the control section, and for restarting 1-3 the operation of the signal when the train resumes its movement. Other features and advantages of my invention will appear as the specification progresses.

I will describe two forms of apparatus em- 20 bodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. l is a diagrammatic view of one form of apparatus. embodying my invention wherein operation of a highway crossing signal is controlled by a train approaching the intersection from one direction only. Fig. 2 is a diagrammatic view of apparatus for governing the operation of a highway crossing signal wherein the apparatus is arranged to 30 be eiiective when a train approaches an intersection from either direction, and which form of apparatus also embodies my invention.

Similar reference characters refer to similar parts in each of the two views.

35 Referring to Fig. l, the reference characters la and lb designate the rails of a stretch of railway over which trafi'ic normally moves in the direction indicated by the arrow, and which rails are intersected by a highway H. A highway 0 crossing signal S is located adjacent the intersection. This signal S may take any one of several different forms for highway crossing signals and, as here shown, is an audible signal in the form of an electric bell. The immediate control of signal S is effected through the medium of a control relay SC, the arrangement being such that when relay SC is deenergized and its back contact is closed current is supplied to signal S over a simple circuit and a warning is 50 sounded. The manner of controlling the relay SC will be described hereinafter.

The track rails la. and lb are divided by insulated rail joints 2 to form two track sections ST and 21 which a train traverses in the order 59 named in approaching the highway when traveling in the normal direction of trafiic. As here shown, the exit end of section. 2T is adjacent the highway H. The combined length of these two track sections is sufiicientto provide a desired warning period for the signal S prior to the arrival of a train atthe intersection when operation of the signal is initiated as the train enters the section 3T. A wayside station RWS, such for example as a passenger or freight station, is located within the track section 3T. Each track section is provided with a track circuit which includes a source of current such as a battery 3 connected across the rails at one end of the section, and a track relay R plus a prefix corresponding to the associated section connected across the rails at the other end of the section.

A track instrument designated by the reference character MI is operatively connected with the rail lb at a selected point in the vicinity of station RWS for actuation thereof in response to the wheels of a train passing over the point at which the track instrument is located. This track instrument is preferably so designed that it has the characteristic of increasing its resistance in response to Vibration of a train passing the location at which the instrument is attached to the rail. The track instrument may take diiierent forms and may be a rail microphone such as disclosed and claimed in the Letters Patent of the United States No. 1,834,677, granted December 1, 1931 to A. J. Sorensen. It is deemed sufiicient for the present application to point out that such rail microphonecomprises an insulating housing which contains two spaced metal electrodes with carbon granules in the space between the electrodes, When the microphone is not vibrated, the resistance between the electrodes through the carbon granules is relatively low but when the microphone is vibrated by a passing train and the carbon granules are agitated the resistance between the electrodes becomes several times the normal resistance. It will be understood, of course, that my invention is not limited to this one form of track instrument and other forms may be used.

A relay D is controlled by the track instrument MI and to that end is provided with a circuit extending from the B terminal of any convenient source of current, such as a battery not shown, through the electrodes and carbon granules of the track instrument Ml, winding of relay D and to the opposite terminal C of the same source of current. The parts are so proportioned that when the track instrument MI is at rest, the flow of current is sufiicient to effectively energize relay D and its front contact 19 is closed, but that when the track instrument is vibrated due to a passing train the flow of current is reduced and the relay is deenergized, or at least is not sufiicently energized, and its front contact i9 is opened and its back contact i8 is closed. Although only one track instrument is shown, it will be understood that additional instruments may be located at selected points along the track and such additional track instruments connected in the circuit of relay D should it seem desirable to do so.

The signal control relay SC is normally energized over a normally closed circuit passing from the terminal B of the current source over front contacts l6 and ll of track relays 3TB and 2TR, respectively, winding of relay SC and to the opposite terminal C of the current source. An alternative energizing circuit for relay SC is provided which extends from the B battery terminal over a front contact ID of a relay SR to be referred to later, front contact 19 of relay D, back contact l6 of relay 3TR, front contact I! of relay 2TR, winding of relay SC and to the C battery terminal. It follows that when both track sections ET and ST are unoccupied and the track relays 2TR and 3TR are picked up, or when the section ST is occupied and section 2T is unoccupied and relays D and SR are picked up, the relay SC is energized, but that when section 2T is cocupied, or when section 2T is unoccupied and section ST is occupied and either relay D or relay SR is down, the relay SC is deenergized. The relay SC is made slightly slow to pick up in character, and consequently it will not pick up in response to pulsating energy which may be supplied to it by relay D momentarily picking up when a train in section 3T is slowly passing over the track instrument MI.

The relay SR is provided with a pickup circuit passing from terminal B, through back contact l3 of relay 3TR, back contact l8 of relay D, winding of relay SR, and to terminal C. A stick circuit for relay SR is also provided and is the same as the pickup circuit except that it includes front contact I I of relay SR instead of back contact I8 of relay D.

When a train enters section 3T, relay 3TR releases to prepare the pickup circuit for relay SR by closing back contact l3, and at its front contact l6 opens the normal energizing circuit for relay SC, which releases and closes back contact M to initiate the operation of signal S. As the train approaches track instrument Ml, relay D is released due to the vibration of track instrument MI and upon releasing completes at its back contact [8, the pickup circuit for relay SR, and at front contact l9 opens a further point in the alternative circuit for relay SC. When relay SR picks up, its front contact ll closes its stick circuit, while its front contact it) closes a point in the alternative operating circuit for relay SC. It will be readily seen that if the train proceeds on through section 3T into section 2T without stopping, relay D remains deenergized to hold the alternative circuit for relay SC open until after it is opened at another point by the release of relay 2TR and operation of signal S under such circumstances, continues until section ET is vacated. If, however, the train stops at the station RWS in section 3T, the relay D picks up as soon as the track instrumentMl comes to rest and closes the alternative circuit for relay SC at front contact IS. The relay SC accordingly picks up and stops the operation of signal S while the train remains standing in section 3T. As soon as movement of the train is again started, the track instrument Ml again becomes operative to effect the release of relay D so that the operation of the signal is again started.

It will be understood that track instrument MI is so located with respect to the station it is effectively vibrated by a train moving in the vicinity of the station, and is vibrated until the train reaches the exit end of section 3T. Additional track instruments may be located at selected points between the station RWS and the exit end of section 3T and relay D controlled by these adsimilar to those of Fig. l. The normal energizing l circuit for the magnet ZTRP of relay IR passes from terminal B, through front contact 48 of relay 3TR, back contact 58 of relay Y, front contact 41 of relay 2TR, winding of magnet ZTRP, and to terminal C. An alternative energizing circuit for magnet 2TRP extends from B terminal over front contact 50 of relay SR, front contact 49 of relay D, back contact 46 of relay 3TR, and thence as before traced.

Relay Y is provided for the purpose of preventing a false operation of signal S occurring when an eastbound train, that is, a train moving from left to right in Fig. 2, has stopped in section 3T and then resumes movement. The relay Y is provided with a pickup circuit passing from terminal B, through front contacts 5| and 42 of relays D and 3TR, respectively, back contact 6t of magnet ITR, winding of relay Y, and to terminal C. Relay Y is also provided with two stick circuits one of which includes back contact 55 of relay 2TR and the front contact 68 of relay Y, and the other of which includes back contact 65 of relay STR and front contact 58 of relay Y.

When a westbound train, that is, a train moving from right to left in Fig. 2, approaches the crossing, the relay Y is not energized since its pickup circuit is held open at front contact 42 of relay 3TR while the train occupies section ST and is then held open at back contact 60 under the control of magnet ITR of the interlocking relay as the train passes over the crossing and occupies section IT, the contact 68 being held open due to the interlocking feature of the relay. Hence, a westbound train approaching the intersection will control the magnet ZTRP of the interlocking relay in the same manner as relay SC of Fig. l is controlled and operation of signal S over back contact 54 of magnet 2'I'RP will be effected when the train first enters section 3T and will continue in operation without interruption until the train passes over the crossing and vacates section 2T in the event the train does not stop at the station, but if the train stops at the station RWS the relay D will be picked up and magnet ETRP will be energized over its alternative circuit and operation of the signal S will be discontinued while the train is standing at the station, operation of the signal being restarted as soon as the train again advances. It will be understood that when a westbound train enters section GT and magnet ITR is released, the contact 5% will not close due to the interlocking feature of the relay and operation of the signal will not be effected as the westbound train recedes from the crossing.

When an eastbound train enters section IT, the magnet ITR will be deenergized and back contact E la will be closed to initiate the operation of signal S. The back contact $0 of magnet ITR Will now be closed and complete the pickup ciraoss isi cuit for relay Y and that relay will be picked up. When relay Y picks up it will prepare its stick circuits at its own front contact 68, and at its back contact 58 will interrupt both the normal and the alternative energizing circuits for magnet Z'I'RP. Magnet Z'IRP will accordingly become deenergized but its back contact 54 will not close owing to the interlocking feature of the relay IR. When the train enters section ET, the track relay 2TB. will be released and at its back contact 55 will complete one of the stick circuits for relay Y. As the train enters section 3T the track relay 3TB will be released and at its back contact 65 will complete the other stick circuit for relay Y so that relay Y will be maintained energized as long as the section 3T is occupied. When an eastbound train passes over the crossing and vacates section IT, the magnet ITR will be reenergized and operation of the signal S will be stopped. The eastbound train upon approaching the vicinity of track instrument M! will cause the relay D to be released but actuation of its contacts at this time willbe without eifect since the circuits controlled by relay D are already open at back contact 58 of relay Y and front contact d6 of relay 3TB. As soon as the eastbound train vacates section 3T, relay 3TB will pick up and at back contact 65 open the existing stick circuit for relay Y. Relay Y will accordingly release and at its back contact 58 again complete a circuit for magnet 2TB? of the interlocking relay and enable the interlocking feature of relay IR to again assume its normal position. Were the relay Y not provided, a false operation of signal S might result should an eastbound train stop at the station and then proceed on out of the stretch. For example, when the train stopped at the station in section 3T the relay D would be picked up, and, with contact 58 deleted from the circuit, would have completed the alternative energizing circuit for magnet ZTRP, which would have picked up and released the interlocking feature of the relay. Then when the train resumed movement the relay D would have been again released and at its front contact 49 would have interrupted the circuit for magnet ETRP and back contact 54 of magnet ZTRP would be closed since the interlocking feature has now been released, and thus operation of signal S would result while this train moved away from the crossing out of section 3T. With the back contact 58 of relay Y included in the energizing circuits for the magnet Z'IRP, such undesired operation of signal S is prevented.

In view of the foregoing, it will be readily apparent that westbound trains moving through sections ST and 2T will cause the magnet ZTRP to control the operation of signal S in identically the same manner that the signal is controlled by signal control relay S0 of Fig; l, and operation of the signal will be discontinued as soon as section ET is vacated for the reasons clearly set forth in the discussion of the operation given in connection with Fig. 1. It will also be seen that as an eastbound train passes through the stretch, the relay Y will be picked up and will remain energized until section ST is vacated, and will accordingly prevent magnet ZTRP being energized by relay D picking up when an eastbound train makes a stop in section 3T. It will be evident that when an eastbound train enters section 3T the pickup circuit for relay SR will be prepared by the closure of back contact d3 of track relay 3TB. and will be subsequently completed at back contact l8a of relay D when the latter relay releases. Theoperation of relay SRat this time, however, is without effect as the alternative circuit for magnet ZTRP in which front contact 50 of relay SR is included is already open at the back contact 58 of relay Y. When the train vacates section 3T, relay 3TB again picks up and at its back contacts i3 and 65 opens the stick circuits for relays SR and Y, respectively, and these relays accor ingly release. 53 of relay Y again closes, the normal energizing circuit for magnet ZTRP is again established.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is to be understood. that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my inyention. Having thus described my invention, what I claim is: V V

1. In combination, a stretch of railway track intersected by a highway and including a track section equipped with a trackrelay, a highway crossing signal located at the intersection, a control relay for said signal, a circuit for said control relay including a back contact of said track relay, 2. track instrument actuated by trains approaching the intersection, a first auxiliary relay under control of said track instrument having a front contact included in said circuit, a second auxiliary relay havinga pickup circuit including a contact of said first auxiliary relay, a contact of said second auxiliary relay included in said circuit, and a stick circuitfor said second auxiliary relay including a contact of said track relay.

2. In combination, astretch of railway track intersected'by a highway and including a track section equipped with a track relay, a highway crossing signal located at the intersection, a con-' When back contact rail of said section, a first auxiliary relay under I the solecontrol of said track instrument; a second auxiliary relay having a pickup circuit under the joint control of said first auxiliary relay and track relay respectively, a stick circuit for said second auxiliary relay under'the sole control of said track relay, and a second circuit for said control relay including a back contact of said track relay and a front contact of each of said auxiliary relays.

3. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a control relay for said signal, a station located along the stretch to one side of the highway, circuitmeans controlled by a train approaching the intersection from the same side as the station to govern the control relay asrequired to operate the signal, a track instrument located at the station and actuated only while a train in the vicinity'of said station is moving, a first relay controlled by said track instrument and deenergized when the instrument is actuated, a second relay, a pickup circuit for said second relay including a back contact of the first relay, a stick circuitfor said secondrelay shunting around said backcontact, and another crossing signal located at the intersection, a control relay for said signal normally energized over a circuit including a front contact of said track relay, train actuated means positioned at a selected location along said section and effectively actuated when a train in the vicinity of such location is moving, an auxiliary relay controlled by said train actuated means and operated in response to actuation of the means, another auxiliary relay, a pickup circuit for said other auxiliary relay including a contact of the first mentioned auxiliary relay and closed when that relay is operated, a stick circuit for said other auxiliary relay including a back contact of the track relay, and an alternative circuit for energizing the control relay and including a front contact of said other auxiliary relay and a normally closed contact of the first mentioned auxiliary relay.

5. In combination, a stretch of railway track intersected by a highway and including a track section equipped with a track relay, a highway crossing signal located at the intersection, a control relay for said signal normally energized over a circuit including a front contact of said track relay, train actuated means positioned at a selected location along said section and effectively actuated when a train in the vicinity of such location is moving, an auxiliary relay controlled by said train actuated means and operated in response to actuation of the means, another auxiliary relay, a pickup circuit for said other auxiliary relay including a contact of the first mentioned auxiliary relay and closed when that relay is operated, a stick circuit for said other auxiliary relay including a back contact of the track relay, an alternative circuit for energizing the control relay and including a front contact of said other auxiliary relay and a normally closed contact of the first mentioned auxiliary relay, and means controlled by a train for preventing said alternative circuit from energizing the control relay when a train occupies the section in receding from the intersection.

6. In combination, a stretch of railway track intersected by a highway and including a track section to one side of the highway, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, a control, relay for said signal and normally energized over a normally closed circuit including a front contact of the track relay, train actuated means positioned at a selected location along the section, a first auxiliary relay controlled by said train actuated means, a second auxiliary relay having a pickup circuit jointly controlled by the track relay and said first auxiliary relay, a stick circuit for said second auxiliary relay including a back contact of the track relay, an alternative circuit for the control relay including a front contact of each of said auxiliary relays as well as a back contact of said track relay, another relay normally deenergized, means controlled by a train when approaching the intersection from the side opposite said track section to energize said other relay, a stick circuit for said other relay including a back contact of said track relay, and a back contact of said other relay interposed in said alternative circuit.

7. In combination, a stretch of railway track intersected by a highway and including a track section spaced from the intersection to one side of the highway, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, a control relay for said signal and normally energized over a normally closed circuit including a front contact of the track relay, a track instrument located at a station along the section and actuated only while a train in the vicinity of said station is moving, a first auxiliary relay controlled by said track instrument and deenergized when the instrument is actuated, a second auxiliary relay, a pickup circuit for said second auxiliary relay including a back contact of the first auxiliary relay, a stick circuit for said second auxiliary relay and including a back contact of said track relay, an alternative circuit for energizing said control relay and including a front contact of each of said auxiliary relays, and another relay controlled by a train when moving between said track section and said intersection and having a contact common to both said normally closed circuit and said alternative circuit.

8. In combination, a stretch of railway track formed into a first and a second track section each provided with a track relay and said first section intersected by a highway, a highway crossing signal at the intersection, a control relay for said signal normally energized over a circuit including a front contact of each of said relays, a track instrument located at a station along said second section and actuated only While a train in the vicinity of said station is moving, a first auxiliary relay controlled by said track instrument and deenergized when the track instrument is actuated, a second auxiliary relay, a pickup circuit for said second auxiliary relay including back contacts of the first auxiliary relay and of the track relay of the second section, a stick circuit for the second auxiliary relay including a back contact of the track relay of said second section, and an alternative circuit for the control relay including a front contact of each of said auxiliary relays as well as a front contact of the track relay of said first track section. a

9. In combination; a stretch of railway track divided into a first, a second and a third track section and having the second section intersected by a highway; a highway crossing signal located at the intersection, two track relays one for the second section and one for the third section, an interlocking relay for controlling the signal and having one magnet energized by a track circuit of the first section and the other magnet normally energized over a circuit including a front contact of each of said track relays, a track instrument associated with the third section, a first auxiliary relay controlled solely by the track instrument, a second auxiliary relay having a pickup circuit controlled jointly by the track relay of the third section and said first auxiliary relay, a stick circuit for said second auxiliary relay controlled solely by said track relay of the third section, an alternative circuit for said other magnet including a front contact of each of said auxiliary relays, another relay, a pickup circuit for said other relay including a back contact of said one magnet, stick circuit means for said other relay including back contacts of said track relays in parallel, and a back contact of said other relay interposed in said alternative circuit.

JAMES J. VANHORN. 

